Antifreeze formulation and sprinkler systems comprising improved antifreezes

ABSTRACT

Antifreezes are provided for deployment in wet sprinkler systems located in cold environments. The antifreezes allow for the wet sprinkler system to be actuated under temperatures below 32° F. Wet sprinklers, sprinkler systems, methods of providing for the control, suppression and/or extinguishment of a fire that occur in a cold environment, and methods of preventing wet sprinklers from freezing also are provided. The sprinklers, sprinkler systems and methods can be used in residential, commercial and storage settings.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of and priority to U.S. ApplicationNo. 62/598,851, filed Dec. 14, 2017; U.S. Application No. 62/598,805,filed Dec. 14, 2017; U.S. Application No. 62/513,000, filed May 31,2017; U.S. Application No. 62/513,043, filed May 31, 2017; and U.S.Application No. 62/513,078, filed May 31, 2017. This application is alsoa continuation-in-part of U.S. application Ser. No. 15/842,282, filedDec. 14, 2017. Each of these applications are hereby incorporated byreference in their entireties.

TECHNICAL FIELD

The present invention relates generally to antifreeze formulations(liquid freeze protectants) for deployment in fire protection sprinklersand sprinkler systems. Methods of preventing freezing and methods ofsuppressing, controlling and/or extinguishing fires, as well as fireprotection sprinklers and systems, also are provided.

BACKGROUND

Fire protection sprinklers often need to be located in cold environmentswhere the temperature is subject to falling below the freezing point ofwater (32° F., 0° C. at sea level), referred to herein as a freezingtemperature. Such cold environments are found in commercial, storage andresidential settings, such as open areas, freezers, cold rooms,passageways, garages, sheds or other areas exposed to freezingtemperatures, for example, unheated buildings in freezing climates orcold-storage rooms. If a conventional sprinkler system is located in acold environment, the water will freeze in the sprinkler head and/orpipe and render the sprinkler unable to actuate or damage the sprinklerand/or piping.

Conventional sprinkler systems are fully filled (charged) with liquids(for example, water) and are referred to as “wet sprinkler systems.” Asis known in the art, these systems include sprinkler heads and piping.

One approach for dealing with cold environments is referred to as a “drysprinkler system.” Dry sprinkler systems are designed such that in theunactuated state, the water is kept out of the portion of the systemthat is located in the cold environment. Only upon activation does thewater enter the portion of the system that is located in the coldenvironment. Dry sprinklers and systems are disclosed in, for example,U.S. Pat. No. 7,559,376, and also include sprinkler heads and piping.

Wet sprinklers, on the other hand, are designed to be filled with aliquid when in the unactuated state. For wet sprinklers that are notplaced in cold environments, the sprinkler can be filled with water.

Another approach for cold environments is the deployment in wetsprinkler systems of liquids having freezing points below the freezingpoint of water, and often are referred to as “antifreezes” or “liquidfreeze protectants.” Early industrial antifreezes included the use ofalcohols, such as methanol. Methanol, however, is flammable, toxic, andtends to be corrosive. Ethylene glycol and propylene glycol havesupplanted methanol as an antifreeze.

The National Fire Protection Association (NFPA) has permitted antifreezein sprinkler systems since at least as early as 1952. Arvidson, J. FireProtect. Eng 21(2):115-32 (2011). The NFPA currently permits a maximumof 38% by volume propylene glycol and a maximum of 48% by volumeglycerin (glycerol) for fire sprinklers, and 48% vol. glycerin and waterantifreezes are currently on the market. However, these two wateradditives, at their highest allowable concentrations have freezingpoints of 0° F. (propylene glycol) and −15° F. (glycerin). The field,however, has experienced various difficulties with these chemicalcomponents. First, propylene glycol cannot be used in systems havingchlorinated polyvinyl chloride (CPVC) pipes. Moreover, these twocomponents, at their highest allowable concentrations, have thepotential of adding heat to a fire, which is measured as the “heatrelease rate.”

As reported by Arvidson, antifreezes have resulted in flashovers uponsprinkler activation. In a tragic incident in Truckee, Calif., anexplosion occurred with a residential sprinkler system containing anantifreeze, which resulted in a fatality and another victim badlyburned.

U.S. Patent Application Publication 2014/0138105 A1 discloses the use ofcarboxylate salts in propylene glycol and glycerol-containing fluids.This publication discloses glycerol concentrations up to 60% wt., theuse of 5% wt. to 50% wt. of a carboxylate salt, like potassium formate,and a reserve of alkalinity to ensure that pH does not drop below 8.

It is therefore desirable to develop antifreezes that have lowerconcentrations of glycerol (glycerin) and salts, and yet have a lowerfreezing point while avoiding flashovers and adding less heat to fires.It is also desirable to avoid the use of ethylene and propylene glycol.

Glycerol (glycerin) has a molecular formula of C₃H₈O₃ and an IUPAC, nameof propane-1,2,3-triol. The structure is depicted below:

SUMMARY

Preferred embodiments provide antifreezes to be deployed (used) in wetsprinklers systems, and such sprinkler systems containing antifreezesfor use in cold environments, such as freezers, cold rooms and locationsexposed to the elements. Additionally, the antifreezes can be deployedin wet and dry sprinkler systems where there may be a risk of freezingtemperatures in parts of the system that would normally be filled withwater. Such a risk would include loss of heating in a warehouse or otherstructure, for example.

The antifreezes preferably comprise water (H₂O) having a conductivity ofno more than 500 μS/cm² at room temperature (although higherconductivity levels are permitted); glycerol; and salts of an organicacids having one of more carboxylic acid groups, wherein glycerol ispresent in a volume percentage of 35% to 48% and the salt(s) are presentin a weight percentage of 0.01% to about 1%, although percentages can behigher, up to and including 2%. Preferably, the antifreeze has a heatrelease rate of no more than 10% higher than the heat release rate of atleast one fire condition selected from the group of conditionsconsisting of just prior to discharge of the antifreeze solution for anyconsecutive 15 second period throughout the discharge of the antifreeze.A possible criteria also can rely upon a the maximum running 60 secondaverage heat release rate measured prior to discharge of the antifreezesolution for any consecutive 15 second period throughout the dischargeof the antifreeze. Alternatively, higher or different heat release rates(e.g., less than 25% higher, less than 20% higher, less than 15% higher,or less than 12% higher, etc.) may be permitted if allowed under currentor future standards or guidelines. The heat release rate can bedetermined using pendent sprinklers having a nominal K-factor of 4.2 and8.0 gpm/(psig)^(1/2) on a supply piping arrangement comprising nominal2-inch diameter steel pipe or larger connected to a pump system capableof providing the required test pressure and flow. Moreover, the heatrelease rate can be determined using a line-burner assembly with fourspray nozzles arranged to discharge heptane at a total flow rate of 1.6gpm (6.0 l/min) resulting in a fire having a nominal total heat releaserate of 1,400 to 3,000 kW. The spray nozzles can be to be spaced 24inches (610 mm) apart on the supply line and 24 inches (610 mm) abovethe floor.

Preferably, the organic acids are at least one selected from the groupconsisting of formic acid (methanoic acid), acetic acid (ethanoic acid),propionic acid, butyric acid (butanoic acid), valeric acid (pentanoicacid), caproic acid (hexanoic acid), lactic acid (2-hydroxypropanoicacid), malic acid (2-hydroxybutanedioic acid), citric acid(2-hydroxypropane-1,2,3-tricarboxylic acid), benzoic acid(benzenecarboxylic acid), oxalic acid (ethanedioic acid), malonic acid(propanedioic acid), succinic acid (butanedioic acid), glutaric acid(pentanedioic acid), adipic acid (hexanedioic acid), pimelic acid(heptanedioic acid), suberic acid (octanedioic acid), azelaic acid(nonanedioic acid), sebacic acid (decanedioic acid). The saltspreferably are potassium salts or sodium salts. Preferred salts arepotassium acetate, potassium formate and potassium succinate.

The antifreezes can further comprise at least one buffer, such as one ormore selected from the group consisting of citrate buffers, carbonatebuffers, phosphate buffers, bicarbonate buffers, triethanolamine, andcombinations thereof.

Preferably, the antifreeze has an electrical shock risk similar to thatof water when discharged onto energized equipment found in dwellingunits, and has a freezing point below −10° F., and more preferably about−15° F. or lower. Preferably, the antifreeze has a pH of about 6 toabout 8, and preferably about neutral to below 8. Additionally, it ispreferable that the conductivity of the antifreeze is no more than 1200μS/cm² at room temperature, although higher conductivities can bepermitted, up to about 2500 μS/cm² at room temperature.

Sprinklers and sprinkler systems (including wet systems) comprisingantifreezes and methods of preventing wet sprinklers and sprinklersystems from freezing using antifreezes also are provided. Wetsprinklers, sprinkler systems, methods of controlling, suppressingand/or extinguishing a fire that occur in a cold environment, andmethods of preventing sprinklers and sprinkler systems from freezingalso are provided.

The systems contain antifreezes, wherein the antifreezes comprise water;glycerol; and a salt of an organic acid having one of more carboxylicacid groups, wherein glycerol is present in a volume percentage of lessthan 48% and the salt is present in a weight percentage of less than 2%,preferably less than 1.75%, more preferably less than 1.5%, still morepreferably less than 1.25%, and still more preferably less than 1%,wherein the wet sprinkler systems can limit temperatures in a ceilingspace under 600° F. (316° C.) during a fire (for example, measured 2 to3 inches below the ceiling space). The antifreezes can comprise one ormore buffers, such as citrate buffers, carbonate buffers, phosphatebuffers, bicarbonate buffers, triethanolamine, and combinations thereof.Preferred salts for the antifreeze include potassium acetate, potassiumformate and potassium succinate. Preferably, the antifreezes have anelectrical shock risk similar to that of water when discharged ontoenergized equipment found in dwelling units, and preferably have afreezing point below −10° F., and more preferably about −15° F. orlower.

The wet sprinkler systems should have at least the portion of the wetsprinkler system that is exposed to the cold environment filled withantifreeze. The wet sprinkler systems also can have various portions toall portions of the wet sprinkler system filled with antifreeze.

Preferred embodiments of the wet sprinkler systems during a fire canlimit the temperature to no more than 200° F. (93° C.) at 5¼ feet (1.6m) above the floor space. Preferred embodiments during a fire can limitthe temperature to no more than 130° F. (93° C.) at 5¼ feet (1.6 m)above the floor space over a continuous 2-minute period. Preferredembodiments during a fire can limit the temperature of the ceilingmaterial ¼ inch (6.4 mm) behind the surface of the ceiling is no morethan 500° F. (260° C.).

Preferred embodiments also include methods of providing for the control,suppression and/or extinguishment of a fire that occurs in a coldenvironment, such as freezers, cold rooms and locations exposed to theelements. The systems used in the methods contain antifreezes, whereinthe antifreezes comprise water; glycerol; and salts of organic acidshaving one of more carboxylic acid groups, wherein glycerol is presentin a volume percentage of less than 48% and the salt is present in aweight percentage of less than 2%, The method can limit temperatures ina ceiling space under 600° F. (316° C.) during a fire (for example,measured 3 inches below the ceiling space). The antifreezes, asdescribed above, can comprise one or more buffers, such as citratebuffers, carbonate buffers, phosphate buffers, bicarbonate buffers,triethanolamine, and combinations thereof. Preferred salts for theantifreeze include potassium acetate, potassium formate and potassiumsuccinate. Preferably, the antifreezes have an electrical shock risksimilar to that of water when discharged onto energized equipment foundin dwelling units, and preferably have a freezing point below −10° F.,and more preferably about −15° F. or lower.

The wet sprinkler systems used according to the methods can have theportion of the wet sprinkler system that is exposed to the coldenvironment is filled with antifreeze. The wet sprinkler systems alsocan have the entirety of the wet sprinkler system filled withantifreeze.

Preferred embodiments of the wet sprinkler systems used according to themethods during a fire can limit the temperature to no more than 200° F.(93° C.) at 5¼ feet (1.6 m) above the floor space. Preferred embodimentsduring a fire can limit the temperature to no more than 130° F. (93° C.)at 5¼ feet (1.6 m) above the floor space over a continuous 2-minuteperiod. Preferred embodiments during a fire can limit the temperature ofthe ceiling material ¼ inch (6.4 mm) behind the surface of the ceilingis no more than 500° F. (260° C.).

There are also provided wet sprinkler systems for use in a coldenvironment, wherein the systems contain antifreeze, wherein theantifreeze comprises water; glycerol; and a salt of an organic acidhaving one of more carboxylic acid groups, wherein glycerol is presentin a volume percentage of less than 48% and the salt is present in aweight percentage of less than 2%, preferably less than 1.75%, morepreferably less than 1.5%, still more preferably less than 1.25%, andstill more preferably less than 1%, wherein the wet sprinkler system canlimit temperatures in a ceiling space to no more than 1400° F. (760° C.)during a fire. The wet sprinkler system can limit temperatures to nomore than 1400° F. (760° C.) at 15 feet 7 inches (4.80 m) above thefloor space. Preferably, wet sprinkler system can limit temperatures tono more than 1.200° F. (649° C.) at 15 feet 7 inches (4.80 m) above thefloor space over a continuous 10-minute period.

Moreover, there are provided methods of controlling a fire that occursin a cold environment, wherein the methods comprise the steps of:providing a wet sprinkler system that is at least partially located incold environment; and deploying in the wet sprinkler system antifreezes,wherein the antifreeze comprise water; glycerol; and a salt of anorganic acid having one of more carboxylic acid groups, wherein glycerolis present in a volume percentage of less than 48% and the salt ispresent in a weight percentage of less than 2%, preferably less than1.75%, more preferably less than 1.5%, still more preferably less than1.25%, and still more preferably less than 1%, wherein the wet sprinklersystem can limit temperatures in a ceiling space to no more than 1400°F. (760° C.) during a fire. The method can limit temperatures to no morethan 1400° F. (760° C.) at 15 feet 7 inches (4.80 m) above the floorspace. Preferably, the method can limit temperatures to no more than1200° F. (649° C.) at 15 feet 7 inches (4.80 m) above the floor spaceover a continuous 10-minute period.

The inventions further provide wet sprinkler systems for use in a coldenvironment, wherein the systems contain an antifreeze, wherein theantifreeze comprises water; glycerol; and a salt of an organic acidhaving one of more carboxylic acid groups, wherein glycerol is presentin a volume percentage of less than 48% and the salt is present in aweight percentage of less than 2%, preferably less than 1.75%, morepreferably less than 1.5%, still more preferably less than 1.25%, andstill more preferably less than 1%, wherein the wet sprinkler system cansuppress a fire involving a Standard Class II commodity. The systems cansuppress a fire in a building with a ceiling no higher than 45.25 feet(13.79 m).

Also provided are methods of suppressing a fire occurring in a coldenvironment and involving a Standard Class II commodity, wherein themethod comprises the steps of: providing a wet sprinkler system that isat least partially located in cold environment; and deploying in the wetsprinkler system an antifreeze, wherein the antifreeze comprises water;glycerol; and a salt of an organic acid having one of more carboxylicacid groups, wherein glycerol is present in a volume percentage of lessthan 48% and the salt is present in a weight percentage of less than 2%,preferably less than 1.75%, more preferably less than 1.5%, still morepreferably less than 1.25%, and still more preferably less than 1%,wherein the wet sprinkler system can suppress a fire involving aStandard Class II commodity. The methods can suppress a fire in abuilding with a ceiling no higher than 45.25 feet (13.79 m).

BRIEF DESCRIPTION OF DRAWINGS

The accompanying drawings, which are incorporated herein and constitutepart of this specification, illustrate exemplary approaches andprotocols for testing embodiments of the invention, and together, withthe general description given above and the detailed description givenbelow, serve to explain the features, characteristics and capabilitiesof aspects of the invention. It should be understood that the preferredembodiments are teachings and examples of the invention as provided bythe appended claims.

FIG. 1 depicts a heptane spray burner assembly illustrated in UL 2901.

FIG. 2 depicts a fire test arrangement illustrated in UL 2901.

FIG. 3 depicts a leakage test manifold assembly illustrated in UL 2901with sprinklers in upright and pendent positions.

DETAILED DESCRIPTION

Antifreeze formulations, in general, take advantage of the phenomenathat impurities lower the freezing point and increases the boiling pointof a pure substance. When formulating antifreeze, it is thereforeadvantageous to add components that are soluble in water and can form ahomogeneous solution. Components that are water soluble are ones thatare polar, ionic and/or contain hydroxyl moieties (—OH groups). Ioniccompounds (i.e., compounds having electrical charges that are either apositive, negative, or both) are more water soluble than their unchargedcompounds. Moreover, ionic compounds add to the entropy of a solution,which contributes to freezing point depression.

All numerical limits and ranges set forth herein include all numbers orvalues thereabout or therebetween of the numbers of the range or limit.The ranges and limits disclosed herein expressly denominate and setforth all integers, decimals and fractional values defined by the rangeor limit. As shown by the following examples: (i), a “range of 1 to 10,”for instance, includes and discloses all values, for example 1, 2, 3,3.5, 3.8, 4, 4.12, 5.981, 6.2, 7, etc. Ranges also can include negativevalues, if recited. A numerical limit of “up to 10,” for instance,includes and discloses all values, for example 0, 0.5, 1, 2, 3, 3.5,3.8, 4, 4.12, 5.981, 6.2, 7, etc., and can include negative valuesdepending on context, as is apparent to one skilled in the art (e.g.,temperatures). In a similar manner, a numerical limit of “at least 10”or “10 or above” includes 10 and all values above 10, as the skilledperson would know.

According to the invention, the water used to make the antifreeze shouldpreferably be soft. A preferred conductivity range at room temperature(68° F. to 79° F.) for the soft water is about 0 to about 500 μS/cm²,preferably 25 to 400 μS/cm², more preferably 30 to 350 μS/cm², stillmore preferably 200 to 350 μS/cm², and even more preferably 320 to 340μS/cm². Values thereabout or there between these integers are includedand can be employed according to the invention. Harder water can besoftened by ion removal approaches, including distillation and reverseosmosis, to the point of becoming effectively deionized. Deionized watercan be used according to the inventions. Deionized water typically hasconductivity ranging from 10 to 50 μS/cm² (typically about 30 μS/cm²).USP-grade water (U.S. Pharmacopeia) also is commercially-available andusable according to the inventions.

Water that is above 500 μS/cm² but below 600 μS/cm², below 700 μS/cm²,below 800 μS/cm², below 900 μS/cm², below 1000 μS/cm², below 1100μS/cm², below 1200 μS/cm², below 1500 μS/cm² or below 2000 μS/cm² isless soft but can be permitted depending on the guideline or standard.

The term “about” (˜) in the context of numerical values and rangesrefers to values or ranges that approximate or are close to the recitedvalues or ranges such that the invention can perform as intended, suchas having a desired rate, amount, degree or extent of components,conductivity, freeze protection, etc., as is apparent from the teachingscontained herein. Thus, these terms encompass values beyond those simplyresulting from random and systematic error.

According to the invention, glycerol and other constituents are added towater to depress the freezing point, such as carboxylates. These otherconstituents include salts of organic acids having one or morecarboxylic acid groups (—COOH). These acids tend to be classified asweak acids, and examples include formic acid (methanoic acid), aceticacid (ethanoic acid), propionic acid, butyric acid (butanoic acid),valeric acid (pentanoic acid), caproic acid (hexanoic acid), lactic acid(2-hydroxypropanoic acid), malic acid (2-hydroxybutanedioic acid),citric acid (2-hydroxypropane-1,2,3-tricarboxylic acid), benzoic acid(benzenecarboxylic acid), oxalic acid (ethanedioic acid), malonic acid(propanedioic acid), succinic acid (butanedioic acid), glutaric acid(pentanedioic acid), adipic acid (hexanedioic acid), pimelic acid(heptanedioic acid), suberic acid (octanedioic acid), azelaic acid(nonanedioic acid), sebacic acid (decanedioic acid). The cation of thesalt can be an alkali metal, such as potassium (K⁺) or sodium (Na⁺).Other cations can be employed, however.

Glycerol should be present in a volume percentage ranging from 35 to48%. Preferably, ethylene and propylene glycols are avoided according tothe invention.

According to the invention, the antifreeze should have high ambienttemperature stability, avoid the flashover problem of previousantifreezes and result in low increases in heat release rates (HRR). Theantifreeze should have hydraulic flow characteristics that allowstransit through pipes and sprinkler assemblies, and preferably havehydraulic flow characteristics that are sufficiently similar to that ofwater to permit functionality. Additionally, corrosiveness andconductivity should be limited, and a stable pH, preferably near neutralshould be maintained. The pH should be slightly acidic (about 6) toslightly basic (about 8). Preferred formulations have a pH ranging from7 to 8, and more preferably 7 to below 8.

UL (Underwriters Laboratories) establishes and publishes criteria forantifreezes for deployment (use) in sprinklers. UL 2901 coversrequirements for antifreezes used in fire sprinkler systems, which ishereby incorporated by reference in its entirety. Currently, noantifreezes are commercially available that meet UL 2901. Theantifreezes according to the invention are contemplated to meet at leastmost requirements of UL 2901, as well as possible changes in the future.

UL 2901 specifies the characteristics of acceptable antifreezes and setsforth testing procedures and parameters. Characteristics of anantifreeze meeting UL 2901 include:

-   -   High Ambient Temperature Stability based on Pour Point,        Viscosity, Specific Gravity, pH and Freeze Point after being        exposed to an elevated temperature for a period of time (158° F.        for 90 days is specified).    -   Temperature Cycling Stability based on Pour Point, Viscosity,        Specific Gravity, pH and Freeze Point after cycling at intended        use temperature extremes for 40 cycles.    -   Electrical conductivity not to exceed 1000 μSiemens/cm² at room        temperature or exhibit an electrical shock risk similar to water        when discharged onto representative energized equipment        typically found in dwelling units. There is an emerging view        that the 1000 μSiemens/cm² level is too low, and therefore the        upper conductivity limit could be as high as about 2500        μSiemens/cm², although upper limits of 1500 μSiemens/cm², 1400        μSiemens/cm², 1300 μSiemens/cm² or 1200 μSiemens/cm² appear more        likely to be accepted by the field. Formulations with such        conductivity levels can be used according to the invention.    -   Corrosion rate of at minimum and maximum concentrations not to        exceed 1.0 mils/year on steel, brass, stainless steel and any        other metal the sprinkler and other components such as pipes,        couplings and valves are composed.    -   Pit depth corrosion rate of at minimum and maximum        concentrations not to exceed 1.0 mils/year on steel, brass,        stainless steel and any other metal the sprinkler and other        components such as pipes, couplings and valves are composed.    -   Exposure to elastomeric materials to assess changes tensile        strength and elongation, volume and weight of the materials        (Natural Rubber, EPDM, BUNA-N, styrene butadiene rubber and any        other elastomer in the sprinkler.    -   Stress corrosion at minimum and maximum concentrations on steel,        brass, stainless steel and any other metal the sprinkler and        other components such as pipes, couplings and valves are        composed.    -   Galvanic action at minimum and maximum concentrations on steel,        brass, stainless steel and any other metal the sprinkler and        other components such as pipes, couplings and valves are        composed.    -   Compatibility with polymers (CPVC and cross-linked        polyethylene).    -   Acceptable toxicity.    -   Heat release rate of no more than 10% above the heat release        rate measured prior to the discharge of the antifreeze.    -   Firefighting effectiveness based upon nominal discharge        coefficient and nominal pressure.

As discussed above, salts of organic acids having one or more carboxylicacid groups (—COOH) are added. These salts lower the freezing point ofthe solution more than 5° F. than without the salts, and decrease theheat release rate when sprayed on fire. The reduction in freezing pointis a colligative property of the solution, i.e., independent of chemicalproperties. For example, potassium acetate contributes two ions permolecule, which adds to the total entropy of the solution lowering thefreezing point. While the addition of most hydrocarbons to a solutionwill add heat to a fire, potassium acetate and compounds having similarmolecular structures reduce the heat of a fire by liberating carbondioxide. Preferred percent range for salts of organic acids having oneor more carboxylic acid groups are 0.01% to 2% wt., preferably 0.1% wt.to 0.5% wt. Betaine, such as trimethylglycine, are zwitterions and canbe used in the same range of weight percentages.

Preferred salts include, but are not limited to:

Potassium Acetate

Potassium Formate

Potassium Succinate

To assist with pH stability, buffers also can be added to theantifreeze. Buffers for use according to the invention include citratebuffers, carbonate buffers, phosphate buffers, bicarbonate buffers andtriethanolamine. Some buffers also provide the beneficial effect ofevolving carbon dioxide during combustion. Preferred percent range ofbuffers are 0.01% to 2% wt., preferably 0.1% wt. to 0.5% wt.

When the antifreeze is deployed in a wet sprinkler system, at least theportion of the wet sprinkler system that is exposed to freezingtemperatures should be filled with the antifreeze. The entirety (orportions thereof, including substantial portions) of the wet sprinklersystem can be filled with the antifreeze.

The invention is further described by the following examples, which areillustrative of the many aspects of the invention, but do not limit theinvention in any manner. Water for the below formulas was sourced fromMarinette County, Wis. The water is soft, and has a conductivity ofabout 320 to 340 μS/cm² at room temperature (68° F. to 79° F.).

Antifreezes according to the present invention can meet the followingcharacteristics:

(A) Conductivity at room temperature of about 2500 μS/cm² or lower,preferably less than 2200 μS/cm², preferably less than 2000 μS/cm²,preferably less than 1500 μS/cm², still preferably less than 1400μS/cm², still preferably less than 1300 μS/cm², still preferably lessthan 1200 μS/cm², still preferably less than 1150 μS/cm², morepreferably less than 1100 μS/cm², more preferably less than 1075 μS/cm²and still more preferably less than 1050 μS/cm² and/or exhibit anelectrical shock risk similar to water when discharged ontorepresentative energized equipment typically found in dwelling units.(B) A heat release rate of no more than 25% above the heat release ratemeasured prior to the discharge of the antifreeze, preferably a heatrelease rate of no more than 20% above the heat release rate measuredprior to the discharge of the antifreeze, still more preferably no morethan 15% above the heat release rate measured prior to the discharge ofthe antifreeze, still more preferably a heat release rate of no morethan 12% above the heat release rate measured prior to the discharge ofthe antifreeze and even still more preferably no more than 10% above theheat release rate measured prior to the discharge of the antifreeze.Current and emerging approaches to evaluating heat release rates arediscussed in greater detail below.(C) A stable pH ranging from about 6 to about 8, and preferably neutralto below 8.(D) A freezing point lower than −10° F., preferably lower than −15° F.,preferably lower than −20° F., more preferably lower than −25° F., stillmore preferably lower than about −30° F., yet more preferably −35° F.,and even lower.(E) Viscosity—The viscosity should be such that the antifreeze can flowthrough the pipes and sprinklers. Preferably between 0.8 to 120 cP(centipoise), more preferably between 0.85 and 110 cP, and still morepreferably between 0.89 and 100 cP.

The invention is further described by the following examples, which areillustrative of the many aspects of the invention, but do not limit theinvention in any manner.

Example 1

The formula of Example 1 (Formula 1) is as follows:

  56% vol. soft water (50.22% wt.)   44% vol. glycerol (49.35% wt.)0.37% wt. potassium acetate 0.09% wt. triethanolamine 0.07% wt.trisodium citrate 0.07% wt. monosodium phosphateFormula 1 has a conductivity of 1008 μSiemens/cm² at 78° F., a pH of 7.9and a freezing point of −30° F. in the absence of deliberate seeding. Arepeated testing yielded a conductivity of 986 μSiemens/cm² at 78° F., apH of 7.9 and a freezing point of −36° F. in the absence of deliberateseeding.

Example 2

The formula of Example 2 (Formula 2) is as follows:

 63% vol. soft water (~57.2% wt.)  37% vol. glycerol (~42.4% wt.) ~0.2%wt. potassium formate ~0.1% wt. potassium succinate ~0.3% wt. betaineFormula 2 has a conductivity of 961 μSiemens/cm² at 78° F., a pH of 7.0and a freezing point of −17° F. in the absence of deliberate seeding.

Example 3

The formula of Example 3 (Formula 3) is as follows:

 63% vol. soft water (~57.1% wt.)  37% vol. glycerol (~42.3% wt.) ~0.3%wt. potassium acetate ~0.1% wt. potassium succinate ~0.3% wt. betaine~0.1% wt. bicarbonateFormula 3 has a conductivity of 1107 μSiemens/cm² at 78° F., a pH of 6.5and a freezing point of −18° F. in the absence of deliberate seeding.

Example 4

The formula of Example 4 (Formula 4) is as follows:

 56% vol. soft water (~55.3% wt.)  44% vol. glycerol (~44.2% wt.) ~0.3%wt. potassium acetateFormula 4 has a conductivity of 1100 μSiemens/cm² at 78° F., a pH of 7.4and a freezing point of −21° F. in the absence of deliberate seeding.Repeated tests of the formula provided respective conductivities of 1060μSiemens/cm² and 1057 μSiemens/cm² at 78° F., pH readings of 7.5 and 7.6and freezing points of −21° F. and −24° F. in the absence of deliberateseeding.

Example 5

The formula of Example 5 (Formula 5 s follows:

 59% vol. soft water (~57.3% wt.)  41% vol. glycerol (~42.5% wt.) ~0.3%wt. potassium acetateFormula 5 has a conductivity of 987 μSiemens/cm² at 78° F., a pH of 7.6and a freezing point of −24.5° F. in the absence of deliberate seeding.

Example 6

The formula of Example 6 (Formula 6) is as follows:

 56% vol. soft water (~55.3% wt.)  44% vol. glycerol (~44.3% wt.) ~0.4%wt. potassium acetateFormula 6 has a conductivity of 1030 μSiemens/cm² at 78° F., a pH of 7.6and a freezing point of −21° F. in the absence of deliberate seeding. Arepeated tested yielded a conductivity of 1005 μSiemens/cm² at 78° F., apH of 7.4 and a freezing point of −21° F. in the absence of deliberateseeding.

Example 7

The formula of Example 7 (Formula 7) is as follows:

 57% vol. soft water (~56.8% wt.)  43% vol. glycerol (~42.8% wt.) ~0.4%wt. potassium acetateFormula 7 has a conductivity of 1060 μSiemens/cm² at 78° F., a pH of 7.5and a freezing point of −20° F. in the absence of deliberate seeding.

Example 8

The formula of Example 8 (Formula 8) is as follows:

  56% vol. soft water (55.4% wt.)   44% vol. glycerol (44.3% wt.) ~0.17%wt. potassium acetate ~0.17% wt. potassium formateFormula 8 has a conductivity of 1010 μSiemens/cm² at 78° F., a pH of 7.8and a freezing point of −20° F. in the absence of deliberate seeding.

Example 9

The formula of Example 9 (Formula 9) is as follows:

  57% vol. soft water (~56.8% wt.)   43% vol. glycerol (~42.8% wt.)~0.37% wt. potassium acetateFormula 9 has a conductivity of 975 μSiemens/cm² at 78° F., a pH of 7.5and a freezing point of −16° F. in the absence of deliberate seeding.

Example 10

The formula of Example 10 (Formula 10) is as follows:

  56% vol. soft water (~55.4% wt.)   44% vol. glycerol (~44.3% wt.)~0.37% wt. potassium acetateFormula 10 has a conductivity of 920 μSiemens/cm² at 78° F., a pH of 7.6and a freezing point of −20.5° F. in the absence of deliberate seeding.

Example 11

The formula of Example 11 (Formula 11) is as follows:

  57% vol. soft water (~56.9% wt.)   44% vol. glycerol (~42.7% wt.)~0.43% wt. potassium acetateFormula 11 has a conductivity of 1058 μSiemens/cm² at 78° F., a pH of8.0 and a freezing point of −23° F. in the absence of deliberateseeding.

Example 12

The formula of Example 12 (Formula 12) is as follows:

  59% vol. soft water (58.4% wt.)   41% vol. glycerol (41.2% wt.) 0.55%wt. potassium acetateFormula 12 has a conductivity of 1010 μSiemens/cm² at 78° F., a pH of7.9 and a freezing point of −16.5° F. in the absence of deliberateseeding.

Example 13—Testing According to UL 2901 and UL 1626

Testing of antifreeze is to be conducted according to UL 2901, whichrefers to and is based on UL 1626 and other standards. UL 2901 and UL1626, and standards referenced therein, and hereby incorporated byreference.

A sprinkler discharging the most concentrated antifreeze solution shallnot cause the total heat release rate from a heptane spray fire toincrease by more than 10 percent above the heat release rate measuredjust prior to the discharge of the antifreeze solution, for anyconsecutive 15 second period throughout the antifreeze solutiondischarge.

Tests are to be conducted using open standard spray pendent sprinklershaving a nominal K-factor of 4.2 and 8.0 gpm/(psig)^(1/2). Thesprinklers are to be installed onto a supply piping arrangementconsisting of nominal 2-inch diameter steel pipe or larger connected toa pump system capable of providing the required test pressure and flow.An electronic pressure transducer is to be installed in the supplypiping at a distance not greater than 10 feet upstream from thesprinklers. The pump is to be connected to a supply of antifreezesolution that is of sufficient quantity to support the duration of thetest.

The fire source is a line-burner assembly with four spray nozzlesarranged to discharge heptane at a total flow rate of 1.6 gpm (6.0l/min) resulting in a fire having a nominal total heat release rate of1,400 to 3,000 kW. The spray nozzles are to be spaced 24 inches (610 mm)apart on the supply line and 2.4 inches (610 mm) above the floor. Metalgrating having nominal dimensions of 94 inches long by 37 inches (940mm) wide with a nominal 0.25 inch (6.4 mm) diameter wire mesh shall beinstalled above the heptane spray nozzles at a height of 38 inches (965mm) above the floor. FIG. 1 provides details of the burner assembly.

Total Heat Release Rate Measurement (HRR)

The total heat release rate is to be measured using a paramagneticoxygen analyzer, velocity probe, and a Type K thermocouple or equivalentunder a calorimeter having diameter of not less than 25 feet (7.6 m).The instrumentation is to be located in the exhaust duct of the heatrelease rate calorimeter at a location that minimizes the influence ofbends or exhaust devices. The heat release rate measurement system is tobe calibrated using an atomized heptane diffusion burner. Thecalibration is to be performed using flows of 1, 2, 3 and 4 gpm (3.8,7.6, 11.4 and 15.2 l/min) of heptane. A burner constructed with ModelF-80-30, 70 degree PLP nozzles manufactured by Monarch Nozzle Co. hasbeen found to be acceptable. The heat release rate is to be calculatedat each of the flows as follows:

${H\; R\; R_{t}} = {16.54 \times 10^{3}V_{e}\frac{298}{T_{e}}\mspace{11mu} A\frac{0.2095 - X_{O\; 2}}{1.076 - {1.36\; X_{O\; 2}}}}$Four tests are to be conducted in accordance with the below table, andFIG. 2 provides details of the test arrangement.

Nominal Sprinkler Sprinkler Elevation Sprinkler K-factor Above InletTest gpm/ the Floor Pressure Range Test (psig)^(1/2) feet (m) psig (kPa)1 4.2 8 (2.4) 10-150 (69-1034) 2 4.2 20 (6.1) 10-150 (69-1034) 3 8.0 8(2.4) 10-100 (69-690)  4 8.0 20 (6.1) 10-100 (69-690) 

After the data collection system is operating, the spray from thefour-nozzle spray burner is to be ignited and then allowed to burnfreely for 120 seconds while flowing a total of 1.6 gpm (6.0 l/min) ofheptane through the line burner assembly. After the 120 second free-burnperiod, the antifreeze solution is to be discharged through the opensprinklers starting at flowing pressure of 10 psig (69 kPa) and thengradually increasing the pressure to the maximum pressure specified inthe above table. At nominal pressure increments of 10 psig (69 kPa), thepressure is to be maintained at each test pressure for a nominal dwelltime of 10 seconds before increasing the pressure to the nextincremental pressure value. Total heat release rate measurements shallbe recorded continuously throughout the duration of the test.

The emerging approach to evaluating heat release rates better takes intoconsideration the intrinsic variability of heptane burners. The approachmodifies UL 2901 to the following:

a sprinkler discharging the most concentrated antifreeze solution shallnot cause the total heat release rate from a heptane spray fire toincrease by more than 10 percent above the maximum running 60 secondaverage heat release rate measured prior to the discharge of theantifreeze solution, for any consecutive 15 second period throughout theantifreeze solution discharge. Based on a one second scan interval, therunning 60 second average heat release rate for the test shall becalculated as follows:

${H\; R\; R_{60\mspace{11mu}{avg}}} = {\frac{1}{60}{\sum\limits_{i = n}^{i = {n + 59}}{H\; R\; R_{i}}}}$In which:

-   -   HRR_(60 avg) is the 60 second average of the Total Heat Release        Rate    -   n is the test time scan number (n=1, 2, 3 . . . etc.) measured        in seconds.        -   n should be between:            -   n=0 seconds; defined as time zero which is the ignition                of the burner assembly and            -   n=61 seconds (test time of 120 seconds); time at which                the antifreeze solution is first discharged.                The maximum running 60 second average heat release rate                is the maximum value of HRR_(60 avg) during the time                period described above.

Fire Fighting Effectiveness

When discharging the most concentrated solution of antifreeze,representative residential sprinklers shall demonstrate compliance withthe fire test requirements described in the Fire Test Section of theStandard for Residential Sprinklers for Fire Protection Service, UL 1626(which is incorporated by reference), when tested as follows:

The test room for these tests is to be configured based upon a ratedsprinkler coverage area of 16 feet by 16 feet (4.9 m by 4.9 in).Recessed pendent and horizontal sidewall residential sprinklers thathave previously demonstrated compliance with the fire tests specified inUL 1626 using water, are to be utilized for these tests. The followingtests are to be conducted in accordance with the Fire Test Section of UL1626 except that the most concentrated solution of antifreeze is to bedischarged from the sprinkler in lieu of water:

-   -   (a) Recessed pendent sprinkler having a nominal discharge        coefficient of 4.9 tested with nominal pressure of 7 psig (48        kPa) at the sprinkler inlet with the frame arms orientated        perpendicular to the short wall;    -   (a1) an alternative approach for (a) is emerging where the        recessed pendent sprinkler having a nominal discharge        coefficient of 4.9 and 175° F. (79° C.) temperature rating        tested with the frame arms orientated perpendicular to the short        wall. First head operation will be at a nominal pressure of 13.5        psig (93 kPa) and pressure with two heads operating will be at a        nominal pressure of 7 psi (48 kPa);    -   (b) Recessed pendent sprinkler having a nominal discharge        coefficient of 4.9 tested with nominal pressure of 100 psig (690        kPa) at the sprinkler inlet with the frame arms orientated        parallel to the short wall;    -   (c) Recessed horizontal sidewall sprinkler having a nominal        discharge coefficient of 4.2 tested with nominal pressure of 23        psig (159 kPa) at the sprinkler inlet with the test fire located        on the far wall (opposite of the wall in which the sprinklers        are installed);    -   (c1) an alternative approach for (c) is emerging where the        recessed horizontal sidewall sprinkler having a nominal        discharge coefficient of 4.2 and 175° F. (79° C.) temperature        rating is tested with the test fire located on the far wall        (opposite of the wall in which the sprinklers are installed).        First head operation will be at a nominal pressure of 30 psig        (207 kPa) and pressure with two heads operating will be at a        nominal pressure of 23 psi (159 kPa); and    -   (d) Recessed horizontal sidewall sprinkler having a nominal        discharge coefficient of 4.2 tested with nominal pressure of 100        psig (690 KPa) at the sprinkler inlet with the test fire located        on the far wall (opposite of the wall in which the sprinklers        are installed).        The flowing pressures indicated above are to be based upon using        an adjusted discharge coefficient (K-factor) for the sprinkler        calculated as follows:

$K_{A} = {7.94\; K_{W}\sqrt{\frac{1}{\gamma_{A}}}}$K_(A)=Sprinkler K-factor discharging the antifreeze solutionK_(W)=Sprinkler K-factor discharging waterγ_(A)=Density of the antifreeze solution at the temperature used fortesting, lbs./ft³

The Fire Test, according to UL 1626, limits temperatures over definedperiods of time at various locations of a fire test arrangement in atest room made of building materials and containing furnishings and/orother items. The test room is representative of enclosures, andcomprises walls, floor(s), ceiling(s), and attendant spaces that areproximal to the wall, floor and ceiling, as apparent to the personskilled in the art, typically 12 inches or closer unless otherwisedefined.

UL 1626 requires that a residential sprinkler shall limit temperatureswhen tested at each rated-spacing referenced in the installationinstructions. Additionally, a maximum of two residential sprinklersshall operate. The sprinklers shall limit temperatures as follows:

(a) The maximum temperature 3 inches (76 mm) below the ceiling atrepresentative locations shall not exceed 600° F. (316° C.).

(b) The maximum temperature 5¼ feet (1.6 m) above the floor shall notexceed 200° F. (93° C.).

(c) The temperature at the location described in (b) shall not exceed130° F. (54° C.) for more than any continuous 2-minute period.

(d) The maximum ceiling material temperature ¼ inch (6.4 mm) behind thefinished ceiling surface shall not exceed 500° F. (260° C.).

Viscosity at Temperature Limitations

The viscosity of each concentration of antifreeze solution shall bedetermined at the temperature limitations specified in themanufacturer's installation instructions and shall correspond to theviscosity specified in the manufacturer's installation instructions.

Viscosity shall be determined as specified in the Standard Test Methodfor Low-Temperature Viscosity of Lubricants Measured by BrookfieldViscometer, ASTM D2983, using antifreeze samples conditioned at theminimum and maximum use temperature limitations specified in themanufacturer's installation instructions for at least 16 hours.

Resistance to Leakage

When tested as described below, antifreeze solution filled andpressurized pipe assemblies with sprinklers attached shall show no signsof leakage for 30 days. Two pipe assemblies that have demonstrated theability resist leakage when filled and pressurized with water, are to befilled with antifreeze solution and pressurized to 350 psig (2413 kPa).One pipe assembly is to be positioned with six nominal k=5.6 orificesprinklers in the vertical upright position, and the second pipeassembly is to be positioned with six nominal k=5.6 orifice sprinklersin the vertical pendent position. See FIG. 3 for diagrams of the typicalpipe assemblies to be used for testing. The pipe joints are to beprepared by applying three wraps of polytetrafluoroethylene (PTFE) pipejoint sealant tape to each male thread for the pipe and sprinklers priorto assembly. The sprinklers are to be assembled with a torque notexceeding 20 ft.-lb (27 N-m). The samples are to be examined at leastweekly and at the end of the 30 day test period for evidence of leakageof solution at the pipe joints and sprinkler closure caps.

Example 14—Testing Results

Formulas were tested by pump method where the sprayer was pumped every 3seconds to maintain relatively constant pressure. Some formulas weretested more than once.

Baseline Average number HRR in of values above kW (no 110% levelPercentage of 110% baseline antifreeze over baseline test HRR over incontinuous 15 Formula applied) HRR 110% baseline second periods 1 4.85.28 53.8% 7.4 2 5.17 5.69 51.3% 9 3 5.04 5.55 43.6% 8 4 4.74 5.22 33.3%5 4.84 5.33 38.4% 6 5 4.97 5.47 59.0% 10 6 4.95 5.45 56.4% 9 5.18 5.7128.2% 4 7 4.80 5.28 48.7% 8 8 4.7 5.17 76.9% 11 9 4.76 5.24 61.5% 8 105.09 5.60 53.8% 8 11 4.72 5.2 61.5% 9.16 12 4.57 5.03   43% 7.04

Formulas 1-12 would meet the UL criteria and/or emerging criteria onHRR. Another formula that utilized 59.1% wt water and 40.6% wt glycerinand 0.3% wt. potassium formate was tested, but would not meet the ULcriteria on HRR.

Example 15—Freeze Testing Under ASTM D 1177-05

ASTM D 1177-05 provides a Standard Test Method for Freezing Point ofAqueous Engine Coolants. The standard defines freezing point as “thetemperature at which crystallization begins in the absence ofsupercooling or the maximum temperature reached immediately afterinitial crystal formation in the case of supercooling.” Section 3.1.1Supercooling is not always encountered if seed crystals form on theirown, however. The methodology of ASTM D 1177-05 employs deliberateseeding to ensure the prevention of supercooling. The seeding isaccomplished by the introduction to the test solution a wire that has asmall amount of frozen test solution on its tip.

The ASTM 1) 1177-05 testing of Formula 1 resulted in a freezingtemperature of −14.6° F.

Example 16—Commercial Systems

UL 1626 described in Example 13 specifically pertains the residentialsystems. However, sprinkler systems are employed in other settings andalso are subject to cold temperatures. The testing criteria areanalogous, but are designed to take into account differentconsiderations.

UL 199 (which is incorporated by reference) is entitled “AutomaticSprinklers for Fire-Protection Service.” UL 199 defines testing forcommercial setting. In a commercial setting, the sprinkler system shouldlimit temperatures in a ceiling space to no more than 1400° F. (760° C.)during a fire. Preferably, the sprinkler system limits the temperatureto no more than 1400° F. (760° C.) at 15 to 16 feet above the floorspace, typically measured at 15′7″ (4.80 m) above the floor space. Stillmore preferably the sprinkler system to no more than 1200° F. (649° C.)at 15 to 16 feet above the floor space, typically measured at 15′7″(4.80 m) above the floor space, over a continuous 10-minute period.Testing approaches and methodologies also are set forth in FireProtection Research Foundation (FPRF) Antifreeze Research for NFPA 2.

Example 17—Storage Systems

A study was conducted on ESFR Sprinklers using antifreeze at UL, whichwas reviewed by the Fire Protection Research Foundation in their study“Antifreeze Solutions in Home Fire Sprinkler Systems.” “FPRF Info forStorage” also is pertinent. These documents disclose the propriety ofusing antifreeze in storage systems where Standard Class II commoditiesare stored. These commodities include noncombustible products that is inslatted wooden crates, solid wood boxes, multiple-layered corrugatedcartons, or equivalent combustible packaging materials, with or withoutpallets. Ceiling heights should be between 45 to 46 feet, preferably45.25 feet (13.79 m).

While the present invention has been disclosed with reference to certainembodiments, numerous modifications, alterations, and changes to thedescribed embodiments are possible without departing from the sphere andscope of the present invention, as described herein. Accordingly, it isintended that the present invention not be limited to the describedembodiments, but that it has the full scope defined by the language setforth herein, and equivalents thereof.

What is claimed is:
 1. An antifreeze to be deployed in a wet sprinklersystem, wherein the antifreeze is produced from ingredients whichcomprise water having a conductivity of no more than 500 μSiemens/cm²(μS/cm²) at a temperature of 68 to 79° F. (20 to 26° C.); glycerol; andat least 0.1 wt. % of one or more organic acid salts, each salt havingone or more carboxylic acid groups, wherein glycerol is present in avolume percentage of 35% to 48%; and wherein the antifreeze has aconductivity of no more than 2500 μS/cm² at a temperature of 68 to 79°F. (20 to 26° C.); and the antifreeze contains no more than 1.5 wt. % ofthe one or more organic acid salts.
 2. The antifreeze according to claim1, wherein the one or more organic acid salts comprise a potassiumand/or sodium salt of one or more organic acids selected from the groupconsisting of formic acid (methanoic acid), acetic acid (ethanoic acid),propionic acid, butyric acid (butanoic acid), valeric acid (pentanoicacid), caproic acid (hexanoic acid), lactic acid (2-hydroxypropanoicacid), malic acid (2-hydroxybutanedioic acid), citric acid(2-hydroxypropane-1,2,3-tricarboxylic acid), benzoic acid(benzenecarboxylic acid), oxalic acid (ethanedioic acid), malonic acid(propanedioic acid), succinic acid (butanedioic acid), glutaric acid(pentanedioic acid), adipic acid (hexanedioic acid), pimelic acid(heptanedioic acid), suberic acid (octanedioic acid), azelaic acid(nonanedioic acid), sebacic acid (decanedioic acid).
 3. The antifreezeaccording to claim 1, wherein the antifreeze further comprises at leastone buffer.
 4. The antifreeze according to claim 3, wherein the bufferis selected from the group consisting of citrate buffers, carbonatebuffers, phosphate buffers, bicarbonate buffers, triethanolamine, andcombinations thereof.
 5. The antifreeze according to claim 1, whereinthe one or more organic acid salts is potassium acetate, potassiumformate, potassium succinate, or a combination of two or more thereof.6. The antifreeze according to claim 1, wherein the antifreeze has a pHof about 6 to about
 8. 7. The antifreeze according to claim 1, where theantifreeze has a conductivity of no more than 1500 μS/cm² at atemperature of 68 to 79° F. (20 to 26° C.).
 8. A wet sprinkler systemfor use in a cold environment, wherein the system comprises theantifreeze of claim
 1. 9. The wet sprinkler system according to claim 8,wherein the wet sprinkler system can limit temperatures measured 2 to 3inches below a ceiling to less than 600° F. (316° C.) during a fire. 10.The wet sprinkler system according to claim 8, wherein the wet sprinklersystem during a fire limits the temperature to no more than 200° F. (93°C.) at 5.25 feet (1.6 m) above a floor space.
 11. The wet sprinklersystem according to claim 8, wherein the wet sprinkler system during afire limits the temperature to no more than 130° F. (54° C.) at 5.25feet (1.6 m) above a floor space over a continuous 2-minute period. 12.The wet sprinkler system according to claim 8, wherein during a fire thetemperature of a ceiling material ¼ inch (6.4 mm) behind a surface of aceiling composed of the ceiling material is no more than 500° F. (260°C.).
 13. The wet sprinkler system according to claim 8, wherein theantifreeze has a heat release rate of no more than 10% higher than aheat release just prior to discharge of the antifreeze solution for anyconsecutive 15 second period throughout the discharge of the antifreeze.14. The wet sprinkler system according to claim 13, wherein the heatrelease rate is determined using pendent sprinklers having a nominalK-factor of 4.2 and 8.0 gpm/(psig)^(1/2) on a supply piping arrangementcomprising nominal 2-inch diameter steel pipe or larger connected to apump system capable of providing the required test pressure and flow.15. The wet sprinkler system according to claim 13, wherein the heatrelease rate is determined using a line-burner assembly with four spraynozzles arranged to discharge heptane at a total flow rate of 1.6 gpm(6.0 l/min) resulting in a fire having a nominal total heat release rateof 1,400 to 3,000 kW.
 16. The wet sprinkler system according to claim15, wherein the spray nozzles are to be spaced 24 inches (610 mm) aparton the supply line and 24 inches (610 mm) above a floor.
 17. A method ofpreventing a wet sprinkler from freezing comprising the step of fillingthe wet sprinkler with the antifreeze according to claim
 1. 18. A methodof preventing a wet sprinkler system from freezing comprising the stepof filling at least a portion of the wet sprinkler system that isexposed to a cold environment with the antifreeze according to claim 1.19. The antifreeze according to claim 1, wherein the antifreeze has afreezing point below −10° F. (−23° C.).
 20. The antifreeze according toclaim 1, wherein the antifreeze has a conductivity of no more than about2,500 μSiemens/cm² (μS/cm²) at a temperature of 68 to 79° F. (20 to 26°C.); a freezing point below −15° F. (−26° C.); and a pH of about 6 to 8.21. A method of controlling a fire that occurs in a cold environment,wherein the method comprises the steps of: providing a wet sprinklersystem that is at least partially located in the cold environment; anddeploying in the wet sprinkler system the antifreeze of claim 1, whereinthe wet sprinkler system can limit temperatures in a ceiling space tounder 600° F. (316° C.) during a fire.
 22. The method according to claim21, wherein deploying the antifreeze in the wet sprinkler systemcomprises completely filling the wet sprinkler system with theantifreeze.
 23. The method according to claim 21, wherein deploying theantifreeze in the wet sprinkler system comprises completely filling aportion of the wet sprinkler system that is exposed to the coldenvironment with the antifreeze.
 24. The method according to claim 21,wherein the wet sprinkler system can limit temperatures measured inches3 inches below a ceiling to under 600° F. (316° C.) during a fire. 25.The method according to claim 21, wherein the wet sprinkler systemduring a fire limits the temperature to no more than 200° F. (93° C.) at5.25 feet (1.6 m) above a floor space.
 26. The method according to claim21 wherein the wet sprinkler system during a fire limits the temperatureto no more than 130° F. (54° C.) at 5.25 feet (1.6 m) above a floorspace over a continuous 2-minute period.
 27. The method according toclaim 21, wherein the wet sprinkler system is deployed proximate aceiling composed of ceiling material, and wherein during a fire thetemperature of the ceiling material ¼ inch (6.4 mm) behind a surface ofthe ceiling is no more than 500° F. (260° C.).
 28. The method of claim21, wherein the wet sprinkler system can limit temperatures in a ceilingspace to no more than 1400° F. (760° C.) during a fire.
 29. A methodaccording to claim 28, herein the wet sprinkler system can limittemperatures to no more than 1,400° F. (760° C.) at 15 feet 7 inches(4.80 m) above the floor space during a fire.
 30. A method according toclaim 29, wherein the wet sprinkler system can limit temperatures to nomore than 1200° F. (649° C.) at 15 feet 7 inches (4.80 m) above thefloor space over a continuous 10-minute period during a fire.
 31. Anantifreeze having a conductivity of no more than about 2,500μSiemens/cm² (μS/cm²) at a temperature of 68 to 79° F. (20 to 26° C.);wherein the antifreeze comprises: up to 63 vol. % water; 35 to 48 vol. %glycerol; and at least 0.1 wt. % of one or more organic acid salts,which comprises a sodium and/or potassium salt of a compound having oneor more carboxylic acid groups; wherein the antifreeze contains no morethan 1.5 wt. % of the one or more organic acid salts.
 32. The antifreezeaccording to claim 31, wherein the organic acid is selected from thegroup consisting of formic acid (methanoic acid), acetic acid (ethanoicacid), propionic acid, butyric acid (butanoic acid), valeric acid(pentanoic acid), caproic acid (hexanoic acid), lactic acid(2-hydroxypropanoic acid), malic acid (2-hydroxybutanedioic acid),citric acid (2-hydroxypropane-1,2,3-tricarboxylic acid), benzoic acid(benzenecarboxylic acid), oxalic acid (ethanedioic acid), malonic acid(propanedioic acid), succinic acid (butanedioic acid), glutaric acid(pentanedioic acid), adipic acid (hexanedioic acid), pimelic acid(heptanedioic acid), suberic acid (octanedioic acid), azelaic acid(nonanedioic acid), sebacic acid (decanedioic acid) or a combination oftwo or more thereof.
 33. The antifreeze according to claim 31, whereinthe salt of the organic acid comprises potassium acetate, potassiumformate, potassium succinate, or a combination of two or more thereof.34. The antifreeze according to claim 31, wherein the antifreeze furthercomprises 0.01 to 2 wt. % of at least one buffer selected from the groupconsisting of carbonate buffers, phosphate buffers, bicarbonate buffers,triethanolamine, and combinations thereof.
 35. The antifreeze accordingto claim 31, wherein the antifreeze has a conductivity of no more thanabout 1,500 μSiemens/cm² (μS/cm²) at a temperature of 68 to 79° F. 36.The antifreeze according to claim 31, wherein the antifreeze comprises0.1 to 0.55 wt. % of the salt of the organic acid.
 37. The antifreezeaccording to claim 31, wherein the antifreeze has a freezing point below−10° F. (−23° C.).
 38. The antifreeze according to claim 31, wherein theantifreeze has a pH of about 6 to
 8. 39. The antifreeze according toclaim 38, wherein the antifreeze has a pH of about 6 to 8; aconductivity of no more than about 1,500 μSiemens/cm² (μS/cm²) at atemperature of 68 to 79° F. (20 to 26° C.); and freezing point below−15° F. (−26° C.).
 40. The antifreeze according to claim 31, wherein theantifreeze comprises 0.1 to 0.55 wt. % potassium acetate, potassiumformate, potassium succinate, or a combination of two or more thereof;and 37 to 48 vol. % glycerol; and the antifreeze further comprisestriethanolamine; trisodium citrate; and monosodium phosphate.
 41. A wetsprinkler system for use in a cold environment, wherein the wetsprinkler system comprises the antifreeze of claim
 31. 42. The wetsprinkler system claim of 41, wherein the antifreeze has a conductivityof no more than about 1,500 μSiemens/cm² (μS/cm²) at a temperature of 68to 79° F.
 43. The wet sprinkler system of claim 41, wherein the entiretyof the wet sprinkler system is filled with the antifreeze.
 44. The wetsprinkler system of claim 41, wherein at least the portion of the wetsprinkler system that is exposed to the cold environment is filled withthe antifreeze.
 45. The wet sprinkler system of claim 41, wherein thewet sprinkler system can limit temperatures in a ceiling space to nomore than 1400° F. (760° C.) during a fire.
 46. The wet sprinkler systemof claim 41, wherein the wet sprinkler system can limit temperatures tono more than 1400° C. F (760° C.) at 15 feet 7 inches (4.80 m) above afloor space during a fire.
 47. The wet sprinkler system of claim 41,wherein the wet sprinkler system can limit temperatures to no more than1200° F. (649° C.) at 15 feet 7 inches (4.80 m) above the floor spaceover a continuous 10-minute period during a fire.
 48. The wet sprinklersystem of claim 41, wherein the wet sprinkler system can suppress a fireinvolving a Standard Class II commodity.
 49. The wet sprinkler system ofclaim 48, wherein the wet sprinkler system suppresses a fire in abuilding with a ceiling no higher than 45.25 feet (13.79 m).
 50. Amethod of preventing a wet sprinkler system used in a cold environmentfrom freezing comprising: filling at least a portion of the wetsprinkler system, which is exposed to the cold environment, with theantifreeze of claim
 31. 51. The method of claim 42, wherein the fireinvolves a Standard Class II commodity, and the method can suppress afire involving a Standard Class II commodity.
 52. The method of claim51, wherein method suppresses a fire in a building with a ceiling nohigher than 45.25 feet (13.79 m).
 53. An antifreeze having a pH of about6 to 8; wherein the antifreeze comprises: up to about 59 vol. % water;at least about 41 vol. % glycerol; and at least 0.1 wt. % of one or moreorganic acid salts, each salt having one or more carboxylic acid groups,and optionally, one or more buffers, wherein the antifreeze has aconductivity of no more than about 2,500 μSiemens/cm² (μS/cm²) at atemperature of 68 to 79° F. (20 to 26° C.); and a freezing point below−15° F. (−26° C.); and the antifreeze contains no more than 1.5 wt. % ofthe one or more organic acid salts.
 54. The antifreeze of claim 53,wherein the antifreeze has a conductivity of no more than about 1,500μSiemens/cm² (μS/cm²) at a temperature of 68 to 79° F. (20 to 26° C.).55. The antifreeze of claim 53, wherein the one or more organic acidsalts comprise potassium acetate, potassium formate, potassiumsuccinate, or a combination of two or more thereof; and the antifreezecomprises one or more of a citrate buffer, a phosphate buffer andtriethanolamine.
 56. The antifreeze of claim 53, wherein the antifreezecomprises 0.1 to 0.55 wt. % potassium acetate and/or potassium formate;and the antifreeze further comprises one or more of triethanolamine,trisodium citrate and monosodium phosphate; and the antifreeze has aconductivity of no more than 1,500 μS/cm².
 57. A wet sprinkler systemfor use in a cold environment, wherein the system contains theantifreeze of claim
 53. 58. The wet sprinkler system of claim 57,wherein the antifreeze further comprises 0.01 to 2 wt. % of one or morebuffers selected from the group consisting of citrate buffers, carbonatebuffers, phosphate buffers, bicarbonate buffers, and triethanolamine.